Page 6 - Wilger Catalog

S P R A Y
R E S O U R C E S
Selecting the Right Spray Quality & Droplet Size
Drift vs. Efficacy
Generally speaking, smaller droplets deposit on the target more effectively than larger droplets, but larger droplets
will drift less. So, when balancing drift control and efficacy, ensure to follow chemical labels and guidelines to designate the required spray quality and droplet size.
Where to find target spray quality or droplet size?
Depending on the chemical, as well as the different methods and modes of applications, some chemical labels may have less/more information. In general, chemical labels will have a description of how it should be applied, in the form of an ASABE spray classification recommendation, or a minimum spray classification (e.g. Spray at least ASABE Coarse). Some chemical label will also stipulate which nozzles can be used.
Example Spray Quality Chart by Type of Application
Application Information:
• Water Volume:
• Nozzles and Pressure: 30 to 40 psi (210 to 275 kPa) when using conventional flat fan nozzles.
Low drift nozzles may require higher pressures for proper performance. Use a combination of nozzles and pressure designed to deliver thorough, even coverage of ASABE coarse spray. Droplet spectrum recommendation for balance of drift & coverage.
Minimum volume requirement on chemical label
Reference max pressure for conventional nozzles like ER series. Try avoid conventional (non-drift reduction) spray tips.
Minimum 22 L per acre.
ASABE S-572.1 Classification Category
Color Code
Estimated VMD Range for Spray Quality*
Contact Insecticide & Fungicide
Systemic Insecticide & Fungicide
Contact Foliar Herbicide
Systemic Foliar Herbicide
Soil-Applied Herbicide
Incorporated Soil-Applied Herbicide
Fertilizer
Extremely Fine (XF)
Purple
Under 60
Very Fine (VF)
Fine (F)
Red
60-105
Orange
106-235
Medium (M)
Yellow
236-340
Coarse (C)
Blue
341-403
Very Coarse (VC)
Green
404-502
Extremely Coarse (XC)
White
503-665
Ultra Coarse (UC)
Black
Over 665
The above table provides general guidelines regarding droplet size and spray quality used in most spray applications.
It is always required that you carefully read and follow updated chemical manufacturers application label and instructions.
*NOTE: VMD range does not classify spray quality. Always ensure spray quality is followed first. VMD is a supplementary figure,and it is normal that nozzles with similar VMD can be classified into different spray qualities.
What about Multi-Tip Spraying? When to consider Double-Down & Angled Spraying
Potential problems with HIGH FLOW applications (15GPA+) with a single spray nozzle:
Spraying high volume out of a single tip can produce droplets that are ‘too large” to be effective for coverage, which make for less effective spray application.
Using multiple spray tips at the same time can provide substantial gains in effective coverage into crops or applications that otherwise would be very difficult to cover; however, multi-tip spraying should not be used without reason.
A typical time to use Multi-Angle spraying:
For improved coverage on a vertical growing target (e.g. wheat) when you are needing to paint both sides of the plant with fungicide.
(e.g. Fusarium Head Blight)
Multi-angle spray for targeting vertical targets. e.g. fusarium head blight
A typical time to use Double-Down spraying:
For high rate applications that rely on consistent coverage in a dense canopy. Use a nozzles to produce a meaningful mix of coarser and finer spray to hit different levels of the canopy.
Multi-tip spray for tough canopies.
e.g. Asian rust on soybeans
#40441-00 ouble-Down
Combo-Rate Nozzle Bodies & Double-Down Turrets
#40440-00 Wye Splitter
Adapter Pairing already-owned nozzles to make a dual nozzle pair:
Much of the time, an operator already has 1-2 nozzles on the sprayer that could be stacked as a pair, so it is an effective way to use existing nozzles to improve spray application with very little cost.
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